PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
OBJECT = TEXT
PUBLICATION_DATE = 2007-05-01
NOTE = "Anomalies and discrepancies in the
NIR DVD Volume set"
END_OBJECT = TEXT
END
---------------------------------------------------
---------------------------------------------------
Lunar polar coverage and the Clementine NIR Dataset
---------------------------------------------------
The processing steps for the NIR mosaics were applied to
data from 70 degrees N to 70 degrees S only. The polar
regions were processed through 'standard' processing steps
only, and the later empirical frame offset and
multiplicative corrections were not applied. This was due
to multiple overlapping frame coverage and the difficulty
in selecting optimal image coverage and deriving a single
representative offset correction value for a given frame to
be corrected.
---------------------------------------------------
---------------------------------------------------
Planetary Data System Data Dictionary Keyword
Discrepancies
---------------------------------------------------
EASTERNMOST_LONGITUDE: For some images (.IMG files), the
value for this keyword may be outside the current valid
range. For example, for CD volume CL_5073 (on DVD DCL_5012)
the image DATA/NI03S357.IMG contains a cartographically
correct value of 360.0132 for EASTERNMOST_LONGITUDE. This
is beyond the current allowed maximum of 360. This occurs
only for those images that contain the 0/360 longitude line
and have a westernmost longitude smaller than 360.
At the time of release of this CD volume, the following PDS
image label keywords were not yet defined in the PDS Data
Dictionary. The definitions are being submitted for
inclusion in the dictionary.
NULL
LOW_REPR_SATURATION
LOW_INSTR_SATURATION
HIGH_INSTR_SATURATION
HIGH_REPR_SATURATION
---------------------------------------------------
---------------------------------------------------
DISCREPANCIES OF PROJECTION OFFSET PARAMETERS AMONG
USGS-PRODUCED PLANETARY DIGITAL GLOBAL MAPS
Eric M. Eliason
7/1/1997
The Issue
---------
This report discusses discrepancies in map projection
Parameters found in the PDS labels on the Mars MDIM,
Magellan F-Map (Venus), and Clementine Digital Map Products
(Earth's Moon) produced by the USGS Astrogeology Team. This
report is important for individuals needing to know the
precise definition of the map projection and cartographic
parameters that describe the image map. There are
differences in the cartographic parameters in each of the
data products that affect the algorithms defining the
relationship between line and sample position in the image
array and the latitude and longitude position on the planet
surface. Specifically, the LINE_PROJECTION_OFFSET and
SAMPLE_PROJECTION_OFFSET parameters have inconsistent
definitions among these data sets.
Additionally, as discussed below there are differences in
the keywords names used to describe the map projection
parameters on the PDS labels due to the evolution of PDS
standards.
Data Products In Question
-------------------------
The Mars MDIM, Magellan F-Map, and Clementine Basemap and
UVVIS Mosaics exist on CD media and are available for wide
distribution to the NASA science community. These data sets
contain global Mosaicked Digital Image Models (MDIM). The
data sets are organized according to a "tiling" scheme that
divides the planet into tiles (or quadrangles). Each tile
represents a specific area on the planet. A tile is stored
as a PDS-labeled image file. For more information on the
data products, refer to the "volinfo.txt" file
located in the document directory on the CD volume sets.
Cartographic Keywords in the PDS Labels
---------------------------------------
The "IMAGE_MAP_PROJECTION" object contained in a PDS label
provides the cartographic parameters necessary to define
any map projection. For the Sinusoidal Equal-Area
Projection only a subset of the cartographic keywords are
required and parameters not applicable will contain "N/A"
in the fields. The list below shows a typical
IMAGE_MAP_PROJECTION group of keywords. For precise
definitions of the keywords, refer to the volinfo.txt file
(located in the document directory) and the dsmap.cat file
(located in the catalog directory.)
OBJECT = IMAGE_MAP_PROJECTION
^DATA_SET_MAP_PROJECTION = "DSMAP.CAT"
COORDINATE_SYSTEM_TYPE = "BODY-FIXED ROTATING"
COORDINATE_SYSTEM_NAME = "PLANETOGRAPHIC"
MAP_PROJECTION_TYPE = "SINUSOIDAL"
MAP_RESOLUTION = 303.2334900
MAP_SCALE = 0.1000000
MAXIMUM_LATITUDE = 7.0000000
MINIMUM_LATITUDE = -0.0132000
EASTERNMOST_LONGITUDE = 6.0131998
WESTERNMOST_LONGITUDE = 0.0000000
LINE_PROJECTION_OFFSET = 2123.6345297
SAMPLE_PROJECTION_OFFSET = 4549.5024429
A_AXIS_RADIUS = 1737.4000000
B_AXIS_RADIUS = 1737.4000000
C_AXIS_RADIUS = 1737.4000000
FIRST_STANDARD_PARALLEL = "N/A"
SECOND_STANDARD_PARALLEL = "N/A"
POSITIVE_LONGITUDE_DIRECTION = EAST
CENTER_LATITUDE = 0.0
CENTER_LONGITUDE = 15.0000000
REFERENCE_LATITUDE = "N/A"
REFERENCE_LONGITUDE = "N/A"
LINE_FIRST_PIXEL = 1
SAMPLE_FIRST_PIXEL = 1
LINE_LAST_PIXEL = 2127
SAMPLE_LAST_PIXEL = 1844
MAP_PROJECTION_ROTATION = 0.0000000
VERTICAL_FRAMELET_OFFSET = "N/A"
HORIZONTAL_FRAMELET_OFFSET = "N/A"
END_OBJECT = IMAGE_MAP_PROJECTION
END
Because of the change in PDS standards the
IMAGE_MAP_PROJECTION group is different between the Mars
MDIM products and the Magellan F-Map and Lunar MDIM
products. The Mars MDIM products were created before the
"final" cartographic projection keywords were defined
and so they are different from the F-MAP and Lunar MDIM
products. Here is a list of the differences in keyword
names:
Mars MDIM Label F-MAP / Lunar MDIM Label
-----------------------------------------------------------
IMAGE_ID (in main label body) changed to PRODUCT_ID
IMAGE_MAP_PROJECTION_CATALOG changed to
IMAGE_MAP_PROJECTION
DATA_SET_MAP_PROJECTION_CATALOG changed to
DATA_SET_MAP_PROJECTION
X_AXIS_FIRST_PIXEL changed to LINE_LAST_PIXEL
X_AXIS_LAST_PIXEL changed to LINE_LAST_PIXEL
Y_AXIS_FIRST_PIXEL changed to
SAMPLE_FIRST_PIXEL
Y_AXIS_LAST_PIXEL changed to
SAMPLE_LAST_PIXEL
X_AXIS_PROJECTION_OFFSET changed to
LINE_PROJECTION_OFFSET
Y_AXIS_PROJECTION_OFFSET changed to
SAMPLE_PROJECTION_OFFSET
Discrepancies with Offset Parameters
-------------------------------------
The LINE_PROJECTION_OFFSET and SAMPLE_PROJECTION_OFFSET
parameters have inconsistent definitions among the
Clementine, F-Map and Mars MDIM data products. This section
describes the differences.
For the Mars MDIM, the offset parameters (called
X_AXIS_PROJECTION_OFFSET and Y_AXIS_PROJECTION_OFFSET) are
used to define line and sample number as a function of
latitude and longitude:
line = INT(X_AXIS_PROJECTION_OFFSET - LAT*MAP_RESOLUTION
+ 1.0)
sample = INT(Y_AXIS_PROJECTION_OFFSET - (LON -
CENTER_LONGITUDE)*MAP_RESOLUTION*COS(LAT) + 1.0)
Note that the addition of 1.0 is part of the equation. This
means the X_AXIS_PROJECTION_OFFSET and
Y_AXIS_PROJECTION_OFFSET are relative to line and sample
0,0 in the image array. Because the direction of positive
longitude is to the west for Mars, there is a "-" after the
Y_AXIS_PROJECTION_OFFSET in the equation.
For the F-MAP, Clementine Basemap, and Clementine UVVIS the
equations are defined as:
line = INT(LINE_PROJECTION_OFFSET - LAT*MAP_RESOLUTION)
sample = INT(SAMPLE_PROJECTION_OFFSET + (LON -
CENTER_LONGITUDE)*MAP_RESOLUTION*COS(LAT))
Note that the addition of 1.0 is not part of the equation.
This means that the offset parameters are relative to line
and sample 1,1. Because the direction of positive longitude
is to the east for Venus and the Moon, there is a "+" after
the SAMPLE_PROJECTION_OFFSET term.
An additional discrepancy exists in the F-MAP volume set.
The LINE_PROJECTION_OFFSET and SAMPLE_PROJECTION_OFFSET
parameters are actually the negative of the value that they
should be. A software patch has been included on the F-MAP
CD-ROMs to correct the projection offset keywords. The name
of the program is PATH and it is stored in the SOFTWARE
directory on the F-MAP volumes.
---------------------------------------------------
---------------------------------------------------
UPPER-CASE AND LOWER-CASE FILE NAMES AND DIRECTORIES
ON CD & DVD VOLUMES THAT CONFORM TO
THE ISO-9660 STANDARDS
Eric M. Eliason
3/1/1997
Names of files stored on an ISO-9660 formatted CD or DVDs
are different among computer systems and operating systems.
Some systems use lower-case file names while other systems
use upper-case file names. Here is a list of how various
operating systems behave with file names:
Sun/Solaris - File names and folders are lower-case
lettering
Macintosh - File names and folders are upper-case
lettering
PC/Windows 95 - File names and folders have the first
Letter upper-case followed by
lower-case lettering.
PC/MS-DOS - File names and folders are upper-case
lettering
PC/Windows 3.1 - File names and folders are lower-case
lettering
Because of the inconsistent case lettering of file names it
was decided to provide file and volume names in the image
index files (index.tab and cumindex.tab) and the source
image index file (srcindx.tab on final volume) to upper-
case lettering. Users desiring to build applications around
these tables will need to convert the file name to the
appropriate case for their systems.
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